This invention relates to electronic devices and power converter circuits for electronic devices.
Alternating current (AC) power is typically supplied from wall outlets and is sometimes referred to as line power. Electronic devices include circuitry that runs from direct current (DC) power. Power converter circuitry is used to convert AC power to DC power. The DC power that is created in this way may be used to power an electronic device. The DC power that is created may also be used to charge a battery in an electronic device.
In some applications, AC to DC power converter circuitry may be incorporated into an electronic device. For example, desktop computers often include AC to DC power converter circuitry in the form of computer power supply units. A computer power supply unit has a socket that receives an AC power cord. With this type of arrangement, the AC power cord may be plugged directly into the rear of the computer to supply AC power without using an external power converter.
Although desktop computers are large enough to accommodate internal power supplies, other devices such as handheld electronic devices and portable computers are not. As a result, typical handheld electronic devices and laptop computers require the use of external power converters. When untethered from the power converter, a handheld electronic device or portable computer may be powered by an internal battery. When AC line power is available, the power converter is used to convert AC power into DC power for the electronic device.
Because users must often carry their power converters with them when they travel, it is generally desirable to make power converters as small as possible. Power converters that are too bulky may be unsightly and difficult to transport.
Despite the benefits of minimizing the size of power converters, it can be difficult to implement power converter size reductions in practical designs. Popular power converter designs typically include inductive components such as transformers, other electrical components such as capacitors and control circuitry, and passive components such as connectors. Components are typically mounted on a printed circuit board.
The size of a power converter can be minimized by minimizing the size of its components. Unfortunately, size reductions, although desirable, may be impractical for many applications. For example, it can be costly to reduce the size of transformer components, because small transformer designs tend to rely on exotic and expensive materials. It is sometimes not acceptable to use connectors of reduced size because of a need to preserve compatibility with existing hardware. Capacitors with specialized designs might permit size reductions, but are generally cost prohibitive. Capacitors with conventional designs may be used that exhibit smaller capacitance values and consume less space, but this tends to lead to power supply inefficiencies.
In view of these considerations, it would be desirable to provide improved power converter systems for electronic devices.